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#!/usr/bin/python
"""This tool reads a Debian package from stdin and emits a yaml stream on
stdout. It does not access a database. Therefore it can be run in parallel and
on multiple machines. The generated yaml contains multiple documents. The first
document contains package metadata. Then a document is emitted for each file.
And finally a document consisting of the string "commit" is emitted."""
import hashlib
import optparse
import sys
import tarfile
import zlib
import lzma
import yaml
from dedup.arreader import ArReader
from dedup.debpkg import process_control, get_tar_hashes
from dedup.hashing import DecompressedHash, SuppressingHash, HashedStream, \
HashBlacklistContent
from dedup.compression import GzipDecompressor, DecompressedStream
from dedup.image import GIFHash, PNGHash
boring_content = set(("", "\n"))
def sha512_nontrivial():
return HashBlacklistContent(hashlib.sha512(), boring_content)
def gziphash():
hashobj = DecompressedHash(GzipDecompressor(), hashlib.sha512())
hashobj = SuppressingHash(hashobj, (ValueError, zlib.error))
hashobj.name = "gzip_sha512"
return HashBlacklistContent(hashobj, boring_content)
def pnghash():
hashobj = PNGHash(hashlib.sha512())
hashobj = SuppressingHash(hashobj, (ValueError,))
hashobj.name = "png_sha512"
return hashobj
def gifhash():
hashobj = GIFHash(hashlib.sha512())
hashobj = SuppressingHash(hashobj, (ValueError,))
hashobj.name = "gif_sha512"
return hashobj
def decompress_tar(filelike, extension):
if extension in (b".lzma", b".xz"):
filelike = DecompressedStream(filelike, lzma.LZMADecompressor())
extension = b""
if extension not in (b"", b".gz", b".bz2"):
raise ValueError("unknown compression format with extension %r" %
extension)
return tarfile.open(fileobj=filelike,
mode="r|" + extension[1:].decode("ascii"))
def process_package(filelike, hash_functions, callback):
af = ArReader(filelike)
af.read_magic()
state = "start"
while True:
try:
name = af.read_entry()
except EOFError:
raise ValueError("data.tar not found")
if name.startswith(b"control.tar"):
if state != "start":
raise ValueError("unexpected control.tar")
state = "control"
tf = decompress_tar(af, name[11:])
for elem in tf:
if elem.name not in ("./control", "control"):
continue
if state != "control":
raise ValueError("duplicate control file")
state = "control_file"
callback(process_control(tf.extractfile(elem).read()))
break
continue
elif name.startswith(b"data.tar"):
if state != "control_file":
raise ValueError("missing control file")
state = "data"
tf = decompress_tar(af, name[8:])
for name, size, hashes in get_tar_hashes(tf, hash_functions):
try:
name = name.decode("utf8")
except UnicodeDecodeError:
print("warning: skipping filename with encoding error")
continue # skip files with non-utf8 encoding for now
callback(dict(name=name, size=size, hashes=hashes))
break
def main():
parser = optparse.OptionParser()
parser.add_option("-H", "--hash", action="store",
help="verify that stdin hash given sha256 hash")
options, args = parser.parse_args()
hash_functions = [sha512_nontrivial, gziphash, pnghash, gifhash]
try:
stdin = sys.stdin.buffer
except AttributeError: # python2
stdin = sys.stdin
dumper = yaml.SafeDumper(sys.stdout)
dumper.open()
if options.hash:
stdin = HashedStream(stdin, hashlib.sha256())
process_package(stdin, hash_functions, dumper.represent)
if options.hash:
stdin.validate(options.hash)
dumper.represent("commit")
dumper.close()
if __name__ == "__main__":
main()
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